This application claims the priority of foreign application number 100 27 570.2, filed in Germany on Jun. 2, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a hinge for pivoting a flap, and, in particular to a hinge for pivoting a flap on a motor vehicle having two linkages or legs which are rotatably connected with one another about at least one axis of rotation.
Within the scope of the present invention, the term xe2x80x9cflapxe2x80x9d includes all types of flaps, doors, lids or other covers which are conventionally connected with the body of a motor vehicle by way of an articulated joint.
According to the prior art, conventional flaps must be set in motion such that during a closing movement they fall into a lock at a minimum speed. The kinetic energy connected with this minimum speed must be sufficiently high in order to press together in a large-surface manner, for example, the sealing of a vehicle body opening to be covered, so that the lock is reliably caused to engage. Only then will the flap close off the vehicle body opening in a secure and sufficiently tight manner.
Additional energy is required for overcoming the friction in the system which must be applied manually by the user. If the flap is closed by way of a handle situated on an interior side, this handle has to be released at a relatively early point in time in order to prevent a pinching of the hand. Since the angle of the flap opening is still relatively large, the flap must already be set into a relatively high-speed motion at this point in time, for example, 1.5 m/s at a rear edge of the flap, in the case of a rear flap. This is often relatively difficult and always carries the risk of contusions.
It is therefore an object of the present invention to provide a hinge of the above-mentioned type having a new mechanical design which aids the closing of a flap. In addition, it should be possible to upgrade known hinges in a simple manner by means of the arrangement according to the invention.
According to the invention, this object is achieved by providing a hinge having a transmission arranged for transmitting a torque occurring during a closing movement of the hinge to a flywheel mass for an intermediate accumulation and subsequent aiding and continuation of the closing movement.
The closing of a flap in a hinge according to the invention is aided by an accumulation of energy during the initial closing movement and a subsequent delivery of this energy after the flap has been let go. Accordingly, a hinge according to the invention comprises, in addition to the actual hinged joint, a transmission which is mechanically coupled with the hinge and includes a flywheel mass. During the movement of the flap at the start of the closing movement, the flywheel mass is caused to carry out a rotary motion. After the flap is released, the energy accumulated in the flywheel mass causes a complete closing at a speed which, in comparison to arrangements according to the prior art, is clearly lower. The resistance of the above-mentioned energy-absorbing structural elements, such as the seal, the air resistance, the bearing friction and the balance of weight, is overcome by the available energy which is intermediately stored in the rotary motion of the flywheel mass.
In principle, a unit comprising a flywheel mass and a transmission, in the following is also called a flywheel transmission and is constructed such that it can also be used on a hinge as a separate and subsequently mounted structural element. Thus, a hinge can be retrofitted to form a flywheel transmission according to the invention. However, a hinge is preferably equipped directly with a flywheel transmission and, in the following, is therefore called a hinge according to the invention.
The transmission with a flywheel mass is situated in an area which is in each case suitable for introducing a torque. Advantageously, according to the available space in an embodiment with very limited space, the flywheel transmission and the hinge are coupled with one another by way of a cardan shaft. However, a compact construction is preferable, in which the flywheel transmission is arranged directly in or on the hinge with a direct mechanical coupling, preferably in the area of an axis of rotation of the hinge.
Also in the case of a small mass or flywheel mass, sufficient energy can be stored in the form of a rotary movement because of a corresponding rotational speed, in order to change the hinge also against the above-described resistances into its closed position or closing position. As a result, an additional mass is added to the weight of the rear flap which does not weigh much itself. For this purpose, the transmission is constructed as a step-up gearing.
The hinge of the flap or door may be a single-joint hinge, a four-joint hinge, a multiple-joint hinge or a gearwheel-type hinge. However, any other joint concept or hinge concept can be used in which rotary motions occur internally which are suitable for controlling a flywheel transmission according to the invention.
In an embodiment of a hinge according to the invention, the flywheel transmission is mounted on the flap side. Thus, for example, when arranged on a trunk lid, it does not present an obstacle during the installation as well as during the loading of a trunk equipped in this manner. In this case, the flywheel transmission introduces its torque into the vehicle-body-fixed part of the hinge or into an element of a multiple-joint hinge or directly by way of a force transmission into the vehicle body.
However, advantageously, the flywheel transmission can also be mounted on the vehicle body or the vehicle-body-fixed part of the hinge so that the pivoted flap is relieved by the additional component. The construction must then be aimed at the fact that a torque or a force must be introduced or transmitted from the site of the flywheel transmission on the vehicle body by way of a lever into the flap or an element of the hinge or of a multiple-joint hinge.
In another embodiment, the flywheel transmission is fastened on an element of a multiple-joint hinge or other hinge. In this case, the flywheel transmission introduces its torque directly or introduces a force by way of a lever into another element of the hinge. A direct introduction of force from the flywheel transmission into the vehicle body or into the flap is also conceivable, a distance from the point of the introduction of force to the pivot serving as the lever arm.
According to a preferred embodiment, when the flap is operated in an unusual to unauthorized manner, an excessive force can act upon the flywheel transmission. This may result in damage or require an unnecessarily solid construction. The danger of excessive pinching forces when closing the flap can also have a negative effect. In a further preferred embodiment, the driving torque is therefore limited by the interposition of an overload clutch if torques occur which are unnecessarily high for the normal operation. As a result, while using simple mechanical elements, a force limitation is implemented in the smallest additional space. Simultaneously, as a result of this measure for combating danger, the entire construction can have a weaker dimensioning.
For improving the comfort during the opening, a counterweight is provided on the flap in the case of known flaps. This counterweight aids the movement of the flap at least during the start of the movement so that not the entire force must be applied manually. As a device for balancing the weight, a spring element in the form of a pneumatic spring may, for example, be provided. However, during the closing, the pneumatic spring simultaneously has to be prestressed for the closing movement. For this purpose, additional energy must therefore be applied during the closing movement. By means of a conventional mechanical design, the target conflict resulting from the above-mentioned requirements between a good closing comfort and simultaneously a good opening comfort can be solved only insufficiently. Particularly, a manual operation of a flap is made still more difficult. In a further preferred embodiment of the present invention, the opening in the case of a hinge according to the invention is not significantly impaired. For this purpose, a deactivation of the flywheel drive of the hinge takes place during the opening in order not to impair the comfort of the operation in this phase. By means of a free-wheel device which, during the closing of the flap, is preferably bridged by a centrifugal clutch, the flywheel transmission is uncoupled only during the flap opening movement. As soon as the transmission is caused to rotate during the closing, the free-wheel device is bridged also in its operating direction, thus in the direction of the free wheeling. Now, during the braking of the flywheel, the additional accumulating device can introduce its torque into the flap under the effect of the centrifugal clutch by way of the transmission.
According to another preferred embodiment of the invention, a movable abutment is provided on the transmission route of the flywheel transmission. Starting from a certain position of the flap, the abutment is switched to be rotatable by way of an unlocking device, such as a locking block. Furthermore, as an alternative, electrical, mechanical or hydraulic devices can be provided for this purpose.
In addition, in the case of elastic hinge or flap constructions, large elastic deformations of individual or several components may occur as a result of the required torque of the flywheel transmission of a hinge according to the invention. The implementation of the above-mentioned characteristics is an effective remedy, so that a further strengthening of the construction will not be necessary.
According to another preferred embodiment, by way of this abutment, which rotates starting from a certain position, the rotating motion is converted to a translational motion. By means of a guidance of force, this translational motion drives a pull-shut device, for example, by way of a rod or a Bowden cable. This pull-shut device is integrated in the vicinity of the flap or the door, or directly in the lock. The pull-shut device has the purpose of more directly introducing the required torque for compressing the flap sealing or door sealing for overcoming the friction of the structural elements and of the lock engaging forces, for example, in the proximity of or directly in the lock. This force can be introduced more effectively compared to the prior art.
In a further preferred embodiment, the pull-shut device is constructed as a lever with an abutment, for example, a sloping ramp and/or a connecting link on the flap in the area of the lock, or is constructed as a mechanism which has the same effect. The pull-shut device is preferably driven by an abutment of a joint according to the invention, which abutment is rotatably released in this position. In a preferred embodiment, the rotating movement of the abutment is converted into a translational movement by way of a coupled compression member, by way of which translational movement, a free end of the compression member in the area of the lock on the flap moves over a sloped flank for generating a very high closing force.
By way of the above-mentioned locking block, this pull-shut device is preferably released only when the flap is almost closed. In this condition, a flap, such as a trunk lid, is already closed so far that a pinching is no longer possible. In particular, a gap at the trunk is already closed in such a condition. Because of the pull-shut device which operates subsequently, the speed of the flap can be reduced in comparison to a normally required closing speed such that the flap reliably continues to move only under the effect of all the above-mentioned counterforces. On the other hand, in the event of a pinching risk, it should be possible to securely brake the flap without the occurrence of injuries caused by pinching. Thus, at this point of the moving sequence, the closing speed can be lowered to below 1 m/s, in which case, without the pull-shut device, speeds of approximately 1.5 m/s would be required.
After the pull-shut operation, the pull-shut device can be moved back into its starting position. Using the above-described combination of the free-wheel clutch and the centrifugal clutch, after the conclusion of the closing operation with the decaying of the effect of the driving torque of the flywheel transmission, a weak spring will be sufficient for resetting the pull-shut device and thereby also moving the movable abutment of the flywheel transmission into a starting position for a new opening operation. Thus, a flywheel transmission or hinge according to the invention is virtually immediately available after the secure closing without any significant waiting period for a new opening. This characteristic is very significant in the daily practice because users very frequently, for example, close a trunk and then open it up again immediately in order to check the just loaded content.
Advantageously, a joint or hinge according to the invention can be used in all rear flaps and swivel doors, etc. which have no fully automatic flap closing device. In addition to rear flaps on automobile, all doors, particularly swivelling doors to be opened in the upward direction, can therefore be closed and opened more easily by hand. A use of a joint according to the invention is also conceivable in the case of forward flaps and/or cabs of trucks. A distribution of forces changed by inclination or sloping is automatically compensated by the above-described characteristics of a hinge according to the invention.
The invention is particularly significant for flaps which open automatically after the triggering of a closing device, for example, by way of remote unlocking from a distance of over 5 m. Here, the opening operation is caused after the operation of the lock, for example, by a pneumatic spring, in which case this operation is not at all hindered or impaired by a joint according to the invention. After the loading, the closing movement is advantageously aided as described above.